Laser diodes emit light when current is passed through the diode. The output radiance of the laser diode varies as the drive current through the diode is varied. The output radiance of the laser diode may also vary due to other factors. For example, the output radiance of the laser diode may vary with age. Also for example, the output radiance of the laser diode may vary as the temperature of the diode varies. This can be problematic in part because the temperature of a laser diode may be affected by ambient temperature changes as well as the historical drive current which results in “self-heating” of the diode.
Color projectors that utilize laser diodes for light generation may suffer from variations in luminance and color balance as a result of aging, temperature changes, and other factors. The luminance of a displayed image may change as the radiance of each color laser diode changes. The color balance may also be affected if different color laser diodes have different responses to factors that affect radiance (e.g., aging, temperature, etc.).